In a variety of well completion operations, a sandface assembly, including screens, is conveyed by a service tool and positioned across a hydrocarbon bearing formation. Upon placement of the sandface assembly, numerous well operations, such as placing a gravel pack in the annulus between the Earth formation and the screens, are performed. Successful completion of these operations typically requires numerous movements of the service tool relative to the sandface assembly to effectuate a variety of flow paths.
For successful execution of a service job, a detailed understanding of the downhole interactions between the service tool/service string and the sandface assembly is required. Specific downhole service tools are actuated by movement of the service string which requires an operator to have substantial knowledge of the downhole service tool as well as an ability to visualize the operation and status of the service tool. Typically, the operator marks the service string at a surface location to track the relative positions of the service tool and the downhole sandface assembly. As the service string is moved, each marked position is assumed to indicate a specific position of the service tool relative to the downhole sandface assembly. This approach, however, relies on substantial knowledge and experience of the operator and is susceptible to inaccuracies due to, for example, extension and contraction of the service string. Moreover, in highly deviated wellbores with difficult trajectories, much of the string movement is lost between the surface and the downhole location due to string buckling, compression, and the like. In such systems where gravel packs are performed, the service tool also can be prone to sticking with respect to the downhole sandface assembly.